Loved the team that I worked with. That was also one of the hardest things about leaving.
The work itself. It is why I stayed there for 3 years before finally giving up on my management team and leaving.
My own work environment was hostile most of the time because of my immediate supervisors unwillingness to actually lead the team. He left most of those tasks to me because I was the only one willing enough to step up into the role.
There is a systemic problem with the Leadership at the office I worked at that they were not willing to fix. I brought many of the issues up to my immediate leadership and when nothing changed I up-channeled to the top. They were not willing to change either so I had to leave the company.